Three-dimensional surveying devices mounted on mobile bodies such as vehicles, for example, acquire three-dimensional data for a measurement target object such as a tunnel. Such three-dimensional surveying devices acquire position information and attitude information for a vehicle by using, for example, a total station or a Global Positioning System (GPS) configured to perform distance measuring and angle measuring, and calculate three-dimensional data for the measurement target object. There is a problem, however, that the GPS cannot be used when the vehicle is traveling in a place where it is difficult for radio waves to reach, such as in a tunnel.
In view of this, JP 2017-20972 (A) discloses a three-dimensional shape measurement device including a distance information acquisition section attached to a mobile body, a position information acquisition section configured to acquire position information for the distance information acquisition section, an inertia information acquisition section configured to acquire first attitude information for the distance information acquisition section, an image information acquisition section configured to image an imaging region, and a calculation section. The calculation section of the three-dimensional shape measurement device described in JP 2017-20972 (A) is configured to calculate absolute position information and absolute attitude information of the distance information acquisition section based on the position information, the first attitude information, and second attitude information for the distance information acquisition section acquired by analyzing a plurality of captured images, and to acquire three-dimensional shape information for a measurement target by performing coordinate conversion on the plurality of pieces of distance information acquired by the distance information acquisition section based on the absolute position information and the absolute attitude information.